The invention relates to a battery unit for battery-operated devices such as cordless telephones, notebook computers, video cameras, etc., provided with an envelope within which one or several electrochemical cells are present and which comprises electrical connection contacts, said envelope having the shape at least approximately of a closed rectangular block with a rectangular upper surface, a rectangular lower surface opposite thereto, long side surfaces, and short side surfaces.
The invention further relates to a battery-operated device provided with such a battery unit.
The use of electrical appliances which are not supplied through the mains, i.e. battery-operated appliances becomes more and more common. The use of portable telephones has particularly increased during the past years, as a result of which a considerable increase in the use of rechargeable batteries has taken place. The mass of the battery accounts for a considerable portion of the total mass of the appliance especially in light portable equipment such as said cordless telephones, but also, for example, notebook computers. It is an object on the one hand to give the appliance the longest possible period of use independently of the mains, while on the other hand it is the object to make the appliance as light as possible. These two objects are mutually conflicting because a long period of use implies a greater battery mass, i.e. a greater weight of the appliance. Considerable research is accordingly devoted to the possibilities of realizing batteries of very small mass but nevertheless high power. Work is going on, for example, in the development of very flat batteries provided with one or several electrochemical cells.